Guinness, formerly (1986–97) Guinness PLC, (1982–86) Arthur Guinness & Sons PLC , and (1886–1982) Arthur Guinness Son & Co. Ltd., former company, incorporated in 1886 as Arthur Guinness Son & Co. Ltd., best known as the brewer of a distinctive dark and creamy stout. In 1997 the company merged with Grand Metropolitan PLC to form Diageo PLC. Guinness remains a brand of that company, which is headquartered in London.

Guinness was founded when Arthur Guinness bought a small brewery in Dublin in 1759. At first the brewery produced a variety of ales and beers, but in 1799 it was decided to concentrate exclusively on porter, a dark beer with a rich head. The beer, later known as stout, prospered and came to be regarded as the national beer of Ireland. Guinness died in 1803, and his son Arthur took over the family business and greatly expanded sales to Great Britain. By 1833 Guinness was the largest brewery in Ireland.

In 1855 Arthur’s son Benjamin Lee Guinness took over the company upon his father’s death. The beer had long had a strong following in the British Isles, and Benjamin spread its fame overseas. Guinness’s stout gained a reputation for its nutritional and invigorating properties, and by 1883 the company was the world’s largest brewery. A brewery opened at Park Royal in London in 1936 was soon outproducing the Dublin site. In the 1950s the company began producing Harp lager to fill demand for lighter brews.

In 1985 the firm acquired Arthur Bell & Sons PLC, a distiller of Scotch whisky, and in 1986 it bought The Distillers Co. PLC, which was the largest Scotch distiller in the world. Guinness’s use of clandestine and apparently illegal stock transactions in acquiring Distillers created a major corporate scandal when these acts became known to the public. Guinness’s merger in 1997 with food and beverage company Grand Metropolitan PLC resulted in a company, Diageo, that was the world’s biggest seller of spirits.

In 1955 the company began publishing The Guinness Book of Records, originally conceived to help settle trivia disputes in pubs; the property was sold in 2001.